Cosmic Dust Adds Uncertainty to Big Bang Ripple Discovery

June 20 (Bloomberg) -- Astronomers who announced in March
that they had detected the first direct evidence of the Big Bang
that formed the universe, said that their observations may have
been clouded by cosmic dust.

The scientists, who reported the interference yesterday in
the journal Physical Review Letters, said it didn’t change
initial data released in March on what they attributed to cosmic
microwave patterns from the beginning of the universe. Now more
data is needed to rule out whether dust truly interfered with
their results, said Jamie Bock, an author of the study and
professor of physics at the California Institute of Technology.

“It’s an amazing discovery so there’s a very high bar”
for the evidence, Matias Zaldarriaga, a theoretical physicist at
the Institute for Advanced Study in Princeton, said in a
telephone interview. “At the moment the most conservative
explanation fits the data. This could just be contamination from
cosmic dust.”

Further experiments are under way and observations of
cosmic dust levels must be awaited, said Zaldarriaga, who wasn’t
involved in the study. “The whole problem is that there’s not
enough data.”

Using a radiation-sensitive telescope stationed in the
South Pole, a team of astronomers led by Harvard University
astrophysicist John M. Kovac spotted cosmic microwave patterns
of the impact of a burst of gravitational energy released less
than an instant -- a trillionth of a trillionth of a trillionth
of a second -- pointing to the birth of the universe 14 billion
years ago. The findings, presented as the signature of the Big
Bang, were announced at a press conference on March 17.

New Information

“Most of the paper remains unchanged, including the actual
data points,” Chao-Lin Kuo, a Stanford University assistant
professor and an author of the study, said in an e-mail. “We
did soften the cosmological interpretation, given new
information” about background levels.

Scientists have theorized that background radiation from
the rapid expansion of the universe can be observed as cosmic
microwaves. Detecting evidence of gravitational waves leftover
from that event would provide the strongest evidence yet of how
the universe began.

The results amounted to direct evidence for the
“inflation” theory of the universe’s origin, said Kovac’s
team, which included scientists from Stanford, the Harvard-Smithsonian Center for Astrophysics and the California Institute
of Technology. Alan Guth, professor of physics at the
Massachusetts Institute of Technology, is the originator of the
inflation theory, which holds that the universe underwent a
period of rapid acceleration outward at its very beginning.

Dust Interference

Interference from the light of cosmic dust could also cause
these results, other scientists said, after seeing the initial
study. Unpublished results of other research measuring the
presence of cosmic dust and models were used to try and rule
that out.

Direct measures of cosmic dust reported in May from the
European Space Agency’s Planck satellite indicated polarization
from cosmic dust may be higher than those models predicted, Bock
said. A combination of the results from the Planck analysis and
the results from the South Pole observations should give a
definite answer, he said.

“I’m afraid people are going to have to be patient,‘‘ Bock
said. ‘‘Until we have direct data. the models can only tell you
so much.’’